The present invention provides metabolic regulators, which are proteins (such as fusion proteins, truncated proteins or full-length proteins) that bind to specific metabolites and which can be used to control the availability of the metabolites in cells, particularly plant cells. The proteins of the invention include one or more metabolic regulator proteins, such as bacterial periplasmic binding proteins (bPBPs) or domains from prokaryotic and eukaryotic proteins that are functionally similar to the bPBPs. The present invention also provides nucleic acid molecules encoding the metabolic regulators, methods of making the nucleic acid molecules, and methods for making transformed organisms, including plants, photosynthetic organisms, microbes, invertebrates, and vertebrates.
The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference in their entirety for all that they disclose, and for convenience are referenced in the following text by reference number and are listed by reference number in the appended bibliography.
Plants need resources in the form of elements such as carbon, nitrogen, sulfur, phosphate, hydrogen, oxygen and minerals, for normal growth and development. The resources can be absorbed from the air and soil in the form of carbon dioxide, ammonium, nitrate, phosphates, water, oxygen and ions. Some resources must be assimilated and are synthesized into more complex molecules such as sugars, lipids, amino acids, nucleotides and a variety of secondary molecules that are necessary for plant growth, development, and reproduction. Many of the molecules, such as carbon and nitrogen, form the building blocks for biological polymers, such as polypeptides, DNA, RNA, starch, and cellulose, which regulate and sustain life. Furthermore, water up-take and usage is also associated with the utilization of the above-mentioned compounds.
Plants must coordinate the up-take, assimilation, distribution, allocation and mobilization of resources in the form of carbon, nitrogen, sulfur, phosphate and ions to maximize growth and development, and to maintain health and their ability of reproduce through fruit and seed production. To coordinate these processes plants have developed complex monitoring and signaling networks that integrate the up-take, synthesis, distribution, and allocation of resources available to the plant (31, 32, 33, 38, 58, 89, 94, 95, 152, 154, 165, 166, 171). Recent findings indicate that plants monitor these processes through a set of receptors called plant glutamate receptors that bind to metabolites, specifically amino acids (31, 38, 49, 60, 99, 154).
There is a need in the art for compositions and methods of controlling the availability of metabolites in cells, particularly plant cells.